Anhydride-functional polymers comprising ene reaction products of unsaturated anhydrides and polyolefins

ABSTRACT

An anhydride-functional polymer is obtained by reacting under ene reaction conditions: 
     (i) an unsaturated anhydride having the structure: ##STR1##  wherein R 1  and R 2  are each independently hydrogen, alkyl of 1 to about 6 carbons, or alkoxy of 1 to about 6 carbons, or a halogen; and 
     (ii) at least one polyolefin having at least two carbon-carbon double bonds in the polyolefin backbone and having an average of at least three carbon atoms in the polyolefin backbone between the carbon-carbon double bonds.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to anhydride-functional polymers obtained byreacting, under ene reaction conditions,

(i) an unsaturated anhydride having the structure: ##STR2## wherein R₁and R₂ are each independently hydrogen, alkyl of 1 to about 6 carbons,or alkoxy of 1 to about 6 carbons, or a halogen; and

(ii) at least one polyolefin having at least two carbon-carbon doublebonds in the polyolefin backbone and having an average of at least threecarbon atoms in the polyolefin backbone between the carbon-carbon doublebonds.

The polyolefin which is reacted under ene reaction conditions with theunsaturated anhydride will have an average of at least three carbonatoms in the backbone between the carbon-carbon double bonds. Thebackbone of such a polyolefin would be comprised primarily of repeatingunits having the structure:

    --[--(CR.sub.3 R.sub.4).sub.x --CHR.sub.5 --CH═CH--]--

wherein each x is individually a number from 2 to about 15; and R₃, R₄and R₅ are each individually hydrogen, or a linear, branched or cyclicaliphatic group of 1 to about 18 carbon atoms. By "primarily" is meantthat at least 60% by weight, and preferably at least 90% by weight, ofthe repeating backbone units of the polyolefin would have thatstructure.

The preferred polyolefin has the structure:

    Z--CH═CH--[--(CR.sub.3 R.sub.4).sub.x --CHR.sub.5 --CH═CH--].sub.n --Z

wherein each x, R₃, R₄ and R₅ is as defined above; each Z isindividually hydrogen, or a linear, branched, or cyclic aliphatic groupof 1 to about 36 carbons; and n is a number between 2 and 5,000.

The anhydride-functional polymers should have an average of at least twoanhydride groups per molecule and are useful as corrosion or scaleinhibitors, thickeners, dispersants, and as reactive agents and/orcrosslinking agents for compounds having functional groups, such asepoxy, hydroxyl or amine groups, which are reactive with anhydridegroups. The anhydride polymers can, therefore, be utilized in a varietyof materials such as plastics, fibers, adhesives, paper sizing, inksand, particularly, coating compositions.

This invention also relates to novel reactive compositions which utilizethe anhydride-functional polymer in combination with one or morematerials which can react with anhydride groups. These reactivecompositions can be reacted at room temperature or force dried attemperatures ranging up to about 350° F. or higher if desired. Whenutilized as reactive crosslinking agents for coatings, theanhydride-functional polymers may be utilized in a variety of coatingapplications, including primers and topcoats as well as clearcoatsand/or basecoats in clearcoat/basecoat compositions.

The reactive compositions typically involve the combination of theanhydride-functional polymer with materials reactive with anhydridessuch as polyepoxides, polyamines, polyols, etc. One preferred reactivecomposition comprises the anhydride-functional polymer and a polyol,preferably a hydroxy-functional polymer, optionally in combination withan epoxide or polyepoxide. Another preferred reactive compositioncomprises the anhydride-functional polymer, an acid-functional compound,an epoxide or polyepoxide, and, optionally, a polyol. All of thesecombinations can provide fast reacting, durable coatings which minimizethe toxicity problems which may be associated with other low temperaturecuring systems.

2. Description of the Prior Art

Some polymers obtained by the reaction of unsaturated anhydrides andolefins are known in the art. Japanese examined patent applicationnumber 48-43191 teaches the Ziegler-Natta copolymerization of alkenylanhydrides with olefins such as ethylene, butene or styrene, in thepresence of a mixed catalyst comprising an organic metal compound and atransition metal compound. U.S. Pat. No. 4,374,235 teaches polymersobtained by the free radical initiated addition polymerization of analkenyl succinic anhydride with one or more vinyl monomers such asmaleic anhydride, maleimides, vinyl acetate, and alkyl vinyl ethers.U.S. Pat. No. 4,599,432 teaches the production of alkenyl succinicanhydride compositions by the reaction of an olefin and maleic anhydridefollowed by the addition of a free radical catalyst to polymerize anyunreacted olefin and maleic anhydride. U.S. Pat. No. 4,927,868 teachesresinous binders obtained by the free-radical initiated copolymerizationof an α-olefin or cyclo-olefin and an olefinically unsaturatedmonoanhydride. U.S. Pat. No. 4,720,555 teaches hydrocarbons substitutedwith at least two anhydride moieties produced by the free-radicalinitiated copolymerization of a specified hydrocarbon and a molar excessof an organic anhydride. U.S. Pat. No. 5,066,742 teaches thefree-radical addition copolymer of a C₂ -C₈ olefin and maleic anhydrideas an aqueous copolymer suspension.

The ene reaction involving unsaturated anhydrides with certain olefinsis also known in the art. U.S. Pat. No. 4,026,867 teaches resinouscondensation products made from (i) the ene reaction adduct of anunsaturated anhydride or acid or ester thereof, with a specifiedunsaturated liquid phenol or oligomer thereof, and (ii) an aldehyde.U.S. Pat. No. 4,107,114 teaches the ene reaction of maleic anhydride andunsaturated polyolefins such as polypentadiene. The resultantanhydride-functional polymer can be subjected to a ring cleavagereaction to produce an acid-functional polymer. U.S. Pat. Nos. 4,396,774and 4,736,044 teach the ene reaction product of an unsaturateddicarboxylic anhydride and an ethylenically unsaturated hydrocarbon inthe presence of a Lewis acid catalyst or a specified boron compound,respectively.

U.S. Pat. No. 4,927,669 teaches the ene reaction of maleic anhydridewith unsaturated fatty acids. U.S. Pat. No. 4,919,925 teaches the enereaction product of α-olefins and unsaturated anhydrides in theproduction of deodorizing compounds.

Unsaturated anhydrides, such as maleic anhydride, and copolymers madefrom maleic anhydride are known in the art. Such anhydride copolymersare heterogeneous with respect to the distribution of anhydride groupsalong the backbone of the polymer due to the abnormal copolymerizationbehavior of maleic anhydride with other monomers, and the acid groupsgenerated from opening these anhydrides by reaction with hydroxyl oramine groups are not highly reactive for further cure reactions, e.g.with epoxy groups, due to steric hindrance arising from the proximity ofthe anhydride ring to the polymer backbone. Such anhydride-functionalpolymers are also relatively viscous and may be difficult to utilize incombination with low levels of solvent. Additionally, such polymers mayform dark colored materials when certain base catalysts, such asN-methyl imidazole, are used to accelerate a subsequent reaction of thepolyanhydride with reactive materials such as hydroxy-functionalcompounds.

Curable compositions comprising polyanhydrides in combination with otherreactive materials are also known in the art. For example, U.S. Pat. No.4,946,744 teaches clearcoat/basecoat combinations involving (i) apolyanhydride, for example, such as that prepared by copolymerization ofmaleic anhydride with (meth)acrylic monomers, and (ii) a polyol. U.S.Pat. No. 4,871,806 teaches curable compositions comprising apolyanhydride, a polyacid, a polyol and an epoxy-functional compound.U.S. Pat. No. 4,859,758 teaches an acid-functional cellulose ester basedpolymer which could be used in combination with a polyanhydride and apolyepoxide.

BRIEF SUMMARY OF THE INVENTION

This invention involves anhydride-functional polymers obtained byreacting, under ene reaction conditions, (i) an unsaturated anhydrideand (ii) a defined unsaturated hydrocarbon. Preferably, theanhydride-functional polymer will comprise at least 15% by weight ofanhydride groups. If desired, the anhydride-functional polymers soformed can be further modified by hydrogenation or by graftcopolymerization with ethylenically unsaturated monomers under graftcopolymerization reaction conditions.

The polyolefins useful in the practice of this invention, and especiallythe preferred cyclooctane-based unsaturated hydrocarbons, permit theincorporation of surprisingly high levels of anhydride while stillmaintaining relatively low viscosity and good flexibility. Theanhydride-functional polymers have excellent performance characteristicsincluding excellent cure kinetics, flexibility of cured films and thecapability of providing higher solid coating formulations to minimizeair pollution concerns. The anhydride-functional polymers can be, ifdesired, fully or partially hydrolyzed to produce acid-functionalpolymers, or they can be directly utilized as crosslinking agents formaterials having an average of at least two functional groups which arereactive with anhydride groups, such as epoxy, hydroxyl or aminefunctionality.

Therefore, this invention also relates to reactive or curablecompositions which comprise (i) the anhydride-functional polymers ofthis invention; and (ii) a compound having an average of at least twofunctional groups per molecule which are reactive with anhydride groups.A particularly preferred curable composition comprises (i) theanhydride-functional polymer and (ii) a hydroxy-functional compoundhaving an average of at least two hydroxyl groups per molecule,optionally in combination with an epoxide or polyepoxide. Anotherpreferred combination comprises (i) the anhydride-functional polymer;(ii) an acid-functional compound having an average of at least two acidgroups per molecule, (iii) an epoxide or polyepoxide, and, optionally,(iv) a hydroxy-functional compound having an average of at least twohydroxyl groups per molecule. Another useful composition comprises (i)the anhydride-functional polymer; and (ii) a polyamine compound havingan average of at least two primary and/or secondary amine groups permolecule. The term "compound" is used in its broadest sense to includemonomers, oligomers and polymers.

Although the curable compositions of this invention can be utilizedwithout solvent in many applications, it is especially preferred toutilize the curable composition of this invention in combination withabout 5% to about 75% by weight, based upon the total weight of themixture, of an inert solvent. It is convenient to provide the reactivecomposition as a multicomponent system which is reactive upon mixing thecomponents. Especially preferred is a two-component system wherein theanhydride-functional polymer and the acid-functional compound, ifutilized, are combined in one package and the epoxy-functional compoundand/or the hydroxy-functional compound provide a second package. The twopackages can then be mixed together to provide the curable compositionimmediately prior to use.

In one preferred application, this invention also relates to coatedsubstrates having a multi-layer decorative and/or protective coatingwhich comprises:

(a) a basecoat comprising a pigmented film-forming polymer; and

(b) a transparent clearcoat comprising a film-forming polymer applied tothe surface of the basecoat composition;

wherein the clearcoat and/or the basecoat comprises the curablecompositions of this invention. The term "film forming polymer" meansany polymeric material that can form a film from evaporation of anycarrier or solvent.

Accordingly, one object of this invention is to provide a novelanhydride-functional polymer by the ene reaction of an unsaturatedanhydride and a specified class of polyolefins. Another object is toprovide improved curable compositions having excellent reactivity at lowtemperatures. It is a further object of this invention to providecoating compositions which may be utilized as primers, topcoats orclearcoats and/or basecoats in clearcoat/basecoat compositions. Anotherobject of this invention is to provide an improved two-package coatingcomposition wherein one package comprises a novel anhydride-functionalpolymer and, optionally, an acid-functional compound, and the otherpackage comprises an epoxy-functional compound and/or ahydroxy-functional compound. Another object of this invention is toprovide coatings having excellent reactivity, durability and corrosionresistance. A further object of this invention is to provide improvedcoating compositions which can be cured at room temperature or forcedried at elevated temperatures. Another object is to provide curablecompositions that are relatively low in viscosity and which can beutilized with reduced amounts of volatile organic solvents. These andother objects of the invention will become apparent from the followingdiscussions.

DETAILED DESCRIPTION OF THE INVENTION

The ene reaction is a well known synthetic reaction in which an olefinhaving an allylic hydrogen reacts thermally with an eneophile withformation of a new sigma-bond to a carbon atom, migration of the allylichydrogen to the eneophile, and a change in the position of the doublebond of the olefin. For example, the ene reaction between maleicanhydride and a linear polyolefin obtained by the metathesis ofcyclooctene would proceed in an idealized, representative fashion asfollows: ##STR3##

Since double bonds are not eliminated, but are merely shifted in thepolyolefin, additional ene reactions can take place at the new locationof the double bond, and since the ene reaction can take place at eithercarbon of the olefin double bond, there will be differing numbers ofcarbon atoms between the double bonds on the polymer backbone. Dependingon the stoichiometry employed, there may be unreacted olefinic segmentsinterspersed among the repeating units having pendent succinic anhydridegroups. If greater than one molar equivalent of unsaturated anhydrideper olefin repeating unit is used, some of the olefin repeating unitswill contain more than one anhydride segment.

Representative discussions of olefin metathesis to produce polyolefinpolymers are given in Irvin, K. J. in Olefin Metathesis, Academic Press,London, 1983; by Grubbs, R. H. in Comprehensive OrganometallicChemistry, Wilkinson, G. et al. (Eds), Vol 8, Pergamon New York (1982);by Dragutan, V. et al., Olefin Metathesis and Ring-OpeningPolymerization of Cyclo-Olefins, 2nd Ed., Wiley Interscience, New York(1985); and by Leconte, M. et al. in Reactions of Coordinated Ligands,Braterman, P. R. (Ed.), Plenum New York (1986).

Representative unsaturated anhydrides which are useful in the practiceof this invention include maleic anhydride, chloromaleic anhydride,itaconic anhydride, citraconic anhydride, methoxymaleic anhydride,ethylmaleic anhydride, etc. Maleic anhydride is especially preferred dueto its relatively low cost and availability.

The preferred polyolefins which are useful in the practice of thisinvention have the structure:

    Z--CH═CH--[--(CR.sub.3 R.sub.4).sub.x --CHR.sub.5 --CH═CH--].sub.n --Z

Polyolefins having repeating units wherein x is less than 2, e.g.polybutadiene, are not useful because high levels of anhydrideincorporation, e.g. more than about 15% by weight, leads to very highviscosities. Especially preferred polyolefins are those wherein x isbetween 4 and 12. Polyolefins wherein n is greater than 5 are generallypreferred because they have a sufficient number of double bonds forconvenient incorporation of relatively high levels of anhydride.Particularly preferred polyolefins are those wherein n is between 2 and100 and especially between 8 and 28. Especially preferred polyolefinsare those wherein R₃, R₄ and R₅ are all hydrogen.

Polyolefins which are especially useful in the practice of thisinvention can be prepared by the olefin metathesis of cyclic olefins,typically by a linear olefin. Metathesis of cyclic olefins withthemselves or other cyclic olefins produces larger cyclic olefins.Metathesis of cyclic olefins with non-cyclic olefins produces ringopened, linear polymeric olefins. For example, metathesis of a mixtureof cyclooctene and small amounts of vinyl cyclohexane in the presence ofa metathesis catalyst yields polyoctenemers possessing methylene and/orcyclohexane end groups. The ratio of vinyl cyclohexane to cyclooctene,catalyst selection and level and reaction temperature controls molecularweight. One such idealized reaction is shown below: ##STR4##

Polyolefins having different alkyl chains between unsaturation sites canbe prepared by the metathesis of cyclic olefin monomers of varioussizes. For example, a similar metathesis of cycloheptene would produceidealized repeating units of ##STR5## and a similar metathesis ofcyclopentene would produce idealized repeating units of ##STR6## Othercyclic olefins which are practical for preparing the polyolefins usefulin this invention include, cyclohexene, cyclononene, cyclodecene,cycloundecene, cyclododecene and norbornene. If desired, mixtures ofcyclic olefins can be used to prepare the polyolefin.

The preparation of useful polyolefins can thus be achieved throughmetathesis. Successive metathesis reactions of cyclic olefins terminatedby the metathesis reaction with a linear olefin furnishes linearpolymers having multiple unsaturation sites. polyoctenemers referred tounder the trade name, Vestenamers, were available from HulsAktiengesellschaft, Marl, Germany.

The metathesis reaction is typically conducted at temperatures rangingfrom 0° C. to about 120° C. Useful molecular weight ranges for thedefined polyolefins useful in this invention can be obtained by themetathesis of a cyclic olefin and a non-cyclic olefin in molar ratiosranging from about 2-1 to 5000-1.

Metathesis catalysts are well known in the art and representativeexamples include the halides, oxyhalides and oxides of tungsten,molybdenum and tantalum. Suitable metathesis catalysts are tungstenhexachloride, tungsten oxytetrachloride, tungsten oxide,tridodecylammonium tungstate, tri(tridecyl)ammonium tungstate,trioctylammonium tungstate, molybdenum pentachloride, molybdenumoxytrichloride, acetylacetonatomolybdenum oxide, tridodecylammoniummolybdate, trioctylammonium molybdate and tantalum pentachloride. Onesuitable catalyst for the metathesis reaction, described by Calderon, etal. in Advances in Organometallic Chemistry 1979 17, 479, is prepared bymixing tungsten hexachloride, ethylaluminum chloride and ethanol under anitrogen atmosphere. The metathesis catalyst is typically present at alevel of at least 0.01 parts for each 100 parts by weight of monomers.

Another process to produce the defined polyolefins of this invention isby molecular weight reduction of high molecular weight polymers astaught by K. W. Scott, N. Calderon, E. A. Ofstead, W. A. Judy and J. P.Ward, Adv. Chem. Ser. 1969 91,399. This process, which is similar to thepreviously described production of ring opened polyolefins, isaccomplished by adding a low molecular weight olefin such as ethylene orbutene to a high molecular weight cycloalkene in the presence of ametathesis catalyst.

1. ANHYDRIDE-FUNCTIONAL POLYMERS

As used herein the term "ene reaction conditions" means reactionconditions sufficient to cause the desired degree of ene reactionbetween the unsaturated anhydride and the polyolefin.

The ene reaction for producing the anhydride-functional polymers whichare useful in the practice of this invention is conducted by admixing anunsaturated anhydride, such as maleic anhydride or a substituted maleicanhydride, with the specified polyolefins and maintaining the reactionat 140° C. to 300° C., and preferably 160° C. to 200° C., until thedesired degree of reaction is obtained. The reaction proceeds in veryhigh yields and virtually all of the anhydride is typicallyincorporated. Remaining unreacted anhydride, if any, can be, if desired,removed by vacuum distillation or other suitable method. The enereaction can be conducted, if desired, in the presence of an inertsolvent such as xylene, toluene, methyl amyl ketone, ethylene glycolmonobutyl ether acetate, etc., or, if the polyolefin is liquid at thereaction temperature, the ene reaction can be conducted without solvent.The anhydride and polyolefin can be mixed in virtually any ratio toprovide any desired degree of anhydride functionality in the finalpolymer. Typically, the mixture will comprise 1% to about 70%, andespecially 15% to about 45% anhydride by weight and the remaining 30% to99%, and especially 85% to 55% by weight being the polyolefin.

For some applications, it is advantageous to minimize any hydrolysis ofthe anhydride-functional polymer by removing any water contaminationduring and/or after manufacture of the polymer by azeotropicdistillation utilizing an inert solvent which is capable of forming anazeotrope with water. Preferred azeotropic solvents include aromatic oraliphatic hydrocarbons or their halogenated derivatives such as benzene,toluene, xylene, ethylbenzene, chlorobenzene, cyclohexane, etc. Xyleneis especially preferred.

It is also sometime useful to filter the resultant polymer solution toremove certain insoluble impurities. One preferred filter media is FP-2diatomaceous earth from Eagle Picher.

2. ACID-FUNCTIONAL COMPOUNDS

The acid-functional compounds which, optionally, can be used incombination with the anhydride-functional polymers of this invention inpreparing curable compositions should have an average of at least twocarboxylic acid groups per molecule. Although low molecular weightdiacids and polyacids such as phthalic acid, succinic acid, adipic acid,azelaic acid, maleic acid, fumaric acid, trimellitic acid and trimesicacid can be utilized in combination with the anhydride-functionalpolymers in the practice of this invention, it is especially preferredto utilize polymeric acid-functional compounds.

Preferably the acid-functional polymer will have a number averagemolecular weight of at least about 400. Typical number average molecularweights of the carboxylic acid-functional polymers will range from about500 to about 30,000. Representative acid-functional polymers includeacrylics, polyesters and polymers prepared by the reaction of anhydrideswith hydroxy-functional polymers as discussed more fully below.

2.A. Carboxylic Acid-Functional Polymers Prepared by the Half-EsterForming Reaction of Anhydrides and Hydroxy-Functional Polymers

Especially preferred as acid-functional compounds in the curablecompositions of this invention are the carboxylic acid-functionalpolymers prepared by the half-ester opening of the cyclic anhydride byreaction with a hydroxyl group on the hydroxy-functional polymer to formone ester group and one acid group.

Typically, the hydroxy-functional polymers will have number averagemolecular weights of at least about 400 and typical number averagemolecular weights will range from about 400 to about 30,000, andespecially 1,000 to about 15,000. Methods of preparinghydroxy-functional polymers are well known in the art and the method ofpreparation of the hydroxy-functional molecule or polymer which isreacted with the cyclic carboxylic anhydride to produce the optionalacid-functional polymer is not critical to the practice of thisinvention. Representative polymers which can be reacted with anhydridesto produce the acid-functional polymers include the hydroxy-functionalpolyethers, polyesters, acrylics, polyurethanes, polycaprolactones, etc.as generally discussed in Sections 2.A.1. through 2.A.5. below.

2 .A. 1.

Polyether polyols are well known in the art and are convenientlyprepared by the reaction of a diol or polyol with the correspondingalkylene oxide. These materials are commercially available and may beprepared by a known process such as, for example, the processesdescribed in Encyclopedia of Chemical Technology, Volume 7, pages257-262, published by Interscience Publishers, Inc., 1951; and inKirk-Othmer Encyclopedia of Chemical Technology, Volume 18, pages638-641, published by Wiley-International, 1982. Representative examplesinclude the polypropylene ether glycols and polyethylene ether glycolssuch as those marketed as Niax® Polyols from Union Carbide Corporation.

2.A.2.

Another useful class of hydroxy-functional polymers are those preparedby condensation polymerization reaction techniques as are well known inthe art. Representative condensation polymerization reactions includepolyesters prepared by the condensation of polyhydric alcohols andpolycarboxylic acids or anhydrides, with or without the inclusion ofdrying oil, semi-drying oil, or non-drying oil fatty acids. By adjustingthe stoichiometry of the alcohols and the acids while maintaining anexcess of hydroxyl groups, hydroxy-functional polyesters can be readilyproduced to provide a wide range of desired molecular weights andperformance characteristics.

The polyester polyols are derived from one or more aromatic and/oraliphatic polycarboxylic acids, the anhydrides thereof, and one or morealiphatic and/or aromatic polyols. The carboxylic acids include thesaturated and unsaturated polycarboxylic acids and the derivativesthereof, such as maleic acid, fumaric acid, succinic acid, adipic acid,azelaic acid, and dicyclopentadiene dicarboxylic acid. The carboxylicacids also include the aromatic polycarboxylic acids, such as phthalicacid, isophthalic acid, terephthalic acid, etc. Anhydrides such asmaleic anhydride, phthalic anhydride, trimellitic anhydride, or NadicMethyl Anhydride (brand name formethylbicyclo[2.2.1]heptene-2,3-dicarboxylic anhydride isomers) can alsobe used.

Representative saturated and unsaturated polyols which can be reacted instoichiometric excess with the carboxylic acids to producehydroxy-functional polyesters include diols such as ethylene glycol,dipropylene glycol, 2,2,4-trimethyl 1,3-pentanediol, neopentyl glycol,1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol,2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol,2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol,1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,1,4-bis(2-hydroxyethoxy)cyclohexane, trimethylene glycol, tetramethyleneglycol, pentamethylene glycol, hexamethylene glycol, decamethyleneglycol, diethylene glycol, triethylene glycol, tetraethylene glycol,norbornylene glycol, 1,4-benzenedimethanol, 1,4-benzenediethanol,2,4-dimethyl-2-ethylenehexane-1,3-diol, 2-butene-1,4-diol, and polyolssuch as trimethylolethane, trimethylolpropane, trimethylolhexane,triethylolpropane, 1,2,4-butanetriol, glycerol, pentaerythritol,dipentaerythritol, etc.

Typically, the reaction between the polyols and the polycarboxylic acidsis conducted at about 120° C. to about 200° C. in the presence of anesterification catalyst such as dibutyl tin oxide.

2.A.3.

Additionally, hydroxy-functional polymers can be prepared by the ringopening reaction of epoxides and/or polyepoxides with primary or,preferably, secondary amines or polyamines to produce hydroxy-functionalpolymers. Representative amines and polyamines include ethanol amine,N-methylethanol amine, dimethyl amine, ethylene diamine, isophoronediamine, etc. Representative polyepoxides include those prepared bycondensing a polyhydric alcohol or polyhydric phenol with anepihalohydrin, such as epichlorohydrin, usually under alkalineconditions. Some of these condensation products are availablecommercially under the designations EPON or DRH from Shell ChemicalCompany, and methods of preparation are representatively taught in U.S.Pat. Nos. 2,592,560; 2,582,985 and 2,694,694.

2.A.4.

Other useful hydroxy-functional polymers can be prepared by the reactionof an excess of at least one polyol, such as those representativelydescribed in Section 2.A.2 above, with polyisocyanates to producehydroxy-functional urethanes. Representative polyisocyanates having twoor more isocyanate groups per molecule include the aliphatic compoundssuch as ethylene, trimethylene, tetramethylene, pentamethylene,hexamethylene, 1,2-propylene, 1,2-butylene, 2,3-butylene, 1,3-butylene,ethylidene and butylidene diisocyanates; the cycloalkylene compoundssuch as 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocanate, and the1,3-cyclopentane, 1,3-cyclohexane, and 1,2-cyclohexane diisocyanates;the aromatic compounds such as m-phenylene, p-phenylene, 4,4'-diphenyl,1,5-naphthalene and 1,4-naphthalene diisocyanates; thealiphatic-aromatic compounds such as 4,4'-diphenylene methane, 2,4- or2,6-toluene, or mixtures thereof, 4,4'-toluidine, and 1,4-xylylenediisocyanates; the nuclear substituted aromatic compounds such asdianisidine diisocyanate, 4,4'-diphenylether diisocyanate andchlorodiphenylene diisocyanate; the triisocyanates such astriphenylmethane-4,4',4"-triisocyanate,1,3,5-triisocyanatebenzeneand2,4,6-triisocyanate toluene; and thetetraisocyanates such as 4,4'-diphenyl-dimethylmethane-2,2'-5,5'-tetraisocyanate; the polymerized polyisocyanates suchas tolylene diisocyanate dimers and trimers, and other variouspolyisocyanates containing biuret, urethane, and/or allophanatelinkages. The polyisocyanates and the polyols are typically reacted attemperatures of 25° C. to about 150° C. to form the hydroxy-functionalpolymers.

2.A.5.

Useful hydroxy-functional polymers can also be conveniently prepared byfree radical polymerization techniques such as in the production ofacrylic resins. The polymers are typically prepared by the additionpolymerization of one or more monomers. At least one of the monomerswill contain, or can be reacted to produce, a reactive hydroxyl group.Representative hydroxy-functional monomers include 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,4-hydroxybutyl methacrylate, 2-hydroxypropyl methacrylate,3-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 4-hydroxypentylacrylate, 2-hydroxyethyl ethacrylate, 3-hydroxybutyl methacrylate,2-hydroxyethyl chloroacrylate, diethylene glycol methacrylate,tetraethylene glycol acrylate, para-vinyl benzyl alcohol, etc. Typicallythe hydroxy-functional monomers would be copolymerized with one or moremonomers having ethylenic unsaturation such as:

(i) esters of acrylic, methacrylic, crotonic, tiglic, or otherunsaturated acids such as: methyl acrylate, ethyl acrylate, propylacrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate,ethylhexyl acrylate, amyl acrylate, 3,5,5-trimethylhexyl acrylate,methyl methacrylate, ethyl methacrylate, propyl methacrylate,dimethylaminoethyl methacrylate, isobornyl methacrylate, t-butylmethacrylate ethyl tiglate, methyl crotonate, ethyl crotonate, etc.;

(ii) vinyl compounds such as vinyl acetate, vinyl propionate, vinylbutyrate, vinyl isobutyrate, vinyl benzoate, vinyl m-chlorobenzoate,vinyl p-methoxybenzoate, vinyl α-chloroacetate, vinyl toluene, vinylchloride, etc.;

(iii) styrene-based materials such as styrene, α-methyl styrene, α-ethylstyrene, α-bromo styrene, 2,6-dichlorostyrene, etc.;

(iv) allyl compounds such as allyl chloride, allyl acetate, allylbenzoate, allyl methacrylate, etc.;

(v) other copolymerizable unsaturated monomers such as ethylene,acrylonitrile, methacrylonitrile, dimethyl maleate:, isopropenylacetate, isopropenyl isobutyrate, acrylamide, methacrylamide, and dienessuch as 1,3-butadiene, etc.

The polymers are conveniently prepared by conventional free radicaladdition polymerization techniques. Frequently, the polymerization willbe catalyzed by conventional initiators known in the art to generate afree radical such as t-butyl peroxyoctoate, t-butyl peroxybenzoate,d-t-butyl peroxide, di-t-amyl peroxide, azobis(isobutyronitrile), cumenehydroperoxide, t-butyl perbenzoate, etc. Typically, the acrylic monomersare heated in the presence of the catalyst at temperatures ranging fromabout 35° C. to about 200° C., and especially 75° C. to 150° C., toeffect the polymerization. The molecular weight of the polymer can becontrolled, if desired, by the monomer selection, reaction temperatureand time, and/or the use of chain transfer agents as is well known inthe art.

Especially preferred polymers in the practice of this invention forreaction with the cyclic anhydride to produce the carboxylicacid-functional polymers are hydroxy-functional polyesters andhydroxy-functional acrylic polymers. An especially preferredhydroxy-functional polymer is the addition polymerization reactionproduct of (a) 5 to 100, and especially 10 to about 40, weight percentof a hydroxy-functional ethylenically unsaturated monomer and (b) 0 to95, and especially 60 to about 90, weight percent of at least one otherethylenically unsaturated monomer copolymerizable with thehydroxy-functional monomer.

The cyclic carboxylic acid anhydrides useful in the practice of thisinvention to produce the carboxylic acid-functional half-ester productby reaction with the hydroxy-functional compound can be any monomericaliphatic or aromatic cyclic anhydride having one anhydride group permolecule. Representative anhydrides include phthalic anhydride,3-nitrophthalic anhydride, 4-nitrophthalic anhydride, 3-flourophthalicanhydride, 4-chlorophthalic anhydride, tetrachlorophthalic anhydride,tetrabromophthalic anhydride, tetrahydrophthalic anhydride,hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinicanhydride, dodecenylsuccinic anhydride, octylsuccinic anhydride, maleicanhydride, dichloromaleic anhydride, glutaric anhydride, adipicanhydride, chlorendic anhydride, itaconic anhydride, citraconicanhydride, endo-methylenetetrahydrophthalic anhydride,cyclohexane-1,2-dicarboxylic anhydride, 4-cyclohexene-1,2dicarboxylicanhydride, 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride,5-norbornene-2,3-dicarboxylic anhydride,1,4-cyclohexadiene-1,2-dicarboxylic anhydride,1,3-cyclopentanedicarboxylic anhydride, diglycolic acid anhydride, etc.Maleic anhydride is especially preferred because of its reactivity andrelatively low cost. Other useful anhydrides include those anhydrideshaving a free carboxyl group in addition to the anhydride group such astrimellitic anhydride, aconitic anhydride, 2,6,7-naphthalenetricarboxylic anhydride, 1,2,4-butane tricarboxylic anhydride,1,3,4-cyclopentane tricarboxylic anhydride, etc.

The reaction of the hydroxy-functional compound and the cyclic anhydridecan be conducted at temperatures ranging up to about 150° C. but shouldnormally be conducted at temperatures less than about 75° C., preferablyless than 65° C., and most preferably between about 35° C. to 60° C. Thereaction temperature is maintained until the reaction has proceeded toprovide the desired amount of half-ester groups on the acid-functionalcompound. Normally, as a convenient measure of the extent of thereaction, the reaction will be continued until no change in the amountof residual unreacted anhydride can be observed, and will generallyinvolve reacting at least about 70%, and preferably at least 95%, of theavailable anhydride. If the subsequent end use of the acid-functionalpolymer can tolerate the remaining free anhydride, if any, no separationor removal of the excess unreacted anhydride is necessary. If the enduse of the acid-functional polymer requires that it be free of anyunreacted anhydride, the reaction can be continued until substantiallyall of the anhydride has reacted, or the free anhydride may be removedby vacuum distillation or other techniques well known in the art.

The level of anhydride reacted with the hydroxy-functional compound needonly be sufficient to provide the final desired acid value of theacid-functional compound. Typically the reaction would be conducted byadmixing the polyol and the anhydride at levels to provide at leastabout 0.3 and normally about 0.7 to 1.0 anhydride groups for eachhydroxyl group. By conducting the reaction at temperatures less thanabout 75° C. the carboxylic acid groups formed as part of the half-esterare not appreciably reactive with the hydroxyl groups themselves and sothey do not compete with the ring opening half-ester reaction of theremaining anhydrides.

In order to conduct the reaction at these relatively low temperatures,it is preferred to utilize an esterification catalyst. The catalystshould be present in sufficient amount to catalyze the reaction andtypically will be present at a level of at least about 0.01%, andnormally from about 0.05% to about 3.0%, based upon the weight of thecyclic anhydride. Catalysts which are useful in the esterificationreaction of the anhydride with the hydroxy-functional molecule includemineral acids such as hydrochloric acid and sulfuric acid; alkali metalhydroxides such as sodium hydroxide; tin compounds such as stannousoctoate, or dibutyltin oxide; aliphatic or aromatic amines, especiallytertiary alkyl amines, such as triethylamine; and aromatic heterocyclicamines such as N-methyl imidazole and the like. Especially preferred areN-methyl imidazole and triethylamine.

Although the reaction between the hydroxy-functional compound and theanhydride can be conducted in the absence of solvent if the materialsare liquid at the reaction temperature, it is normally preferred toconduct the reaction in the presence of an inert solvent such as esters,ketones, ethers or aromatic hydrocarbons. If ,desired, theacid-functional molecule can be utilized as the solvent solution, or,optionally, all or part of the inert solvent may be removed, e.g. bydistillation, after the reaction is completed.

After the reaction is completed, it is frequently desirable to add a lowmolecular weight alcohol solvent, such as isobutanol or isopropanol, tothe acid-functional at a level of about 5 to 35 percent by weight toprovide stabilization on storage.

2.B. Carboxylic Acid-Functional Polymers Prepared From UnsaturatedAcid-Functional Monomers

Useful acid-functional polymers can also be conveniently prepared by thefree radical addition polymerization of unsaturated acids such as maleicacid, acrylic acid, methacrylic acid, crotonic acid, etc. along with oneor more unsaturated monomers. Representative monomers include the estersof unsaturated acids, vinyl compounds, styrene-based materials, allylcompounds and other copolymerizable monomers as representatively taughtin Section 2.A.5. of this specification. The monomers which areco-polymerized with the unsaturated acid should be free of anyfunctionality which could react with the acid groups during thepolymerization.

2.C. Carboxylic Acid-Functional Polymers Prepared From Polyols andPolyacids

Other useful acid-functional polymers include polyester polymersobtained from the reaction of one or more aromatic and/or aliphaticcarboxylic acids or their anhydrides and one or more aliphatic and/oraromatic polyols wherein the acid functionality is present in astoichiometric excess over the hydroxy functionality. Representativecarboxylic acids and polyols include those listed in Section 2.A.2. ofthis specification.

3. EPOXY-FUNCTIONAL COMPOUNDS

The curable coatings of this invention may also incorporate at least oneepoxy-functional compound. The epoxy compounds can, if there aresufficient other reactive materials to provide crosslinking, bemonoepoxies or, preferably, a polyepoxide having an average of at leasttwo epoxy groups per molecule.

Representative useful monoepoxides include the monoglycidyl ethers ofaliphatic or aromatic alcohols such as butyl glycidyl ether, octylglycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, dodecylglycidyl ether, p-tert-butylphenyl glycidyl ether, and o-cresyl glycidylether. Monoepoxy esters such as the glycidyl ester of versatic acid(commercially available as CARDURA® E from Shell Chemical Company), orthe glycidyl esters of other acids such as tertiary-nonanoic acid,tertiary-decanoic acid, tertiary-undecanoic acid, etc. are also useful.Similarly, if desired, unsaturated monoepoxy esters such as glycidylacrylate, glycidyl methacrylate or glycidyl laurate could be used.Additionally, monoepoxidized oils can also be used.

Other useful monoepoxies include styrene oxide, cyclohexene oxide,1,2-butene oxide, 2,3-butene oxide, 1,2-pentene oxide, 1,2-hepteneoxide, 1,2-octene oxide, 1,2-nonene oxide, 1,2-decene oxide, and thelike.

It is only necessary that the monoepoxide compounds have a sufficientlylow volatility to remain in the coating composition under the applicableconditions of cure.

Polyepoxides are especially preferred in the reactive coatings of thisinvention. Especially preferred as the poly-functional epoxy compounds,due to their reactivity and durability, are the polyepoxy-functionalcycloaliphatic epoxies. Preferably, the cycloaliphatic epoxies will havea number average molecular weight less than about 2,000 to minimize theviscosity. The cycloaliphatic epoxies are conveniently prepared bymethods well known in the art such as epoxidation of dienes or polyenes,or the epoxidation of unsaturated esters by reaction with a peracid suchas peracetic and/or performic acid.

Commercial examples of representative preferred cycloaliphatic epoxiesinclude 3,4-epoxycyclohexylmethyl3,4-epoxycyclohexane carboxylate (e.g."ERL-4221" from Union Carbide Corp.);bis(3,4-epoxycyclohexylmethyl)adipate (e.g. "ERL-4299" from UnionCarbide Corporation);3,4-epoxy-6-methylcyclohexylmethyl3,4-epoxy-6-methylcyclohexanecarboxylate (e.g. "ERL-4201" from Union Carbide Corp.);bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate (e.g. "ERL-4289" fromUnion Carbide Corp.); bis(2,3-epoxycyclopentyl) ether (e.g. "ERL-0400"from Union Carbide Corp.); dipentene dioxide (e.g. "ERL-4269" from UnionCarbide Corp.);2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-metadioxane (e.g."ERL-4234" from Union Carbide Corp.). Other commercially availablecycloaliphatic epoxies are available from Ciba-Geigy Corporation such asCY 192, a cycloaliphatic diglycidyl ester epoxy resin having an epoxyequivalent weight of about 154. The manufacture of representativecycloaliphatic epoxies is taught in various patents including U.S. Pat.Nos. 2,884,408, 3,027,357 and 3,247,144.

Other polyepoxides potentially useful in the practices of this inventioninclude aliphatic and aromatic polyepoxies, such as those prepared bythe reaction of an aliphatic polyol or poly hydric phenol and anepihalohydrin. Other useful epoxies include epoxidized oils andepoxy-functional copolymers such as acrylic polymers derived fromethylenically unsaturated epoxy-functional monomers such as glycidylacrylate or glycidyl methacrylate in combination with othercopolymerizable monomers such as those listed in 2.A.5 above.

4. HYDROXY-FUNCTIONAL COMPOUNDS

The hydroxy-functional compounds which are useful in combination withthe anhydride-functional polymers to prepare curable compositions in thepractice of this invention should have an average of at least twohydroxyl groups per molecule. Although low molecular weight diols andpolyols such as propylene glycol, 1,6 hexanediol, triethanol amine andpentaerythritol can be utilized in the practice of this invention, it isespecially preferred to utilize polymeric hydroxy-functional compoundssuch as polyethers, polyesters, acrylics, polyurethanes,polycaprolactones, etc.

Preferably the hydroxy-functional polymer will have a number averagemolecular weight of at least about 400. Typical number average molecularweights will range from about 400 to about 30,000, and especially 1,000to about 15,000. In order to provide the fastest rate of reaction duringcure it is preferred in the practice of this invention to utilizehydroxy-functional compounds having predominantly, and preferably all,primary hydroxy functionality.

Representative hydroxy-functional polymers are taught in Sections 2.A.1.through 2.A.5. Especially preferred as the hydroxy-functional polymer isa hydroxy-functional polymer comprising the addition polymerizationreaction product of (a) 10 to about 60 weight percent of ahydroxy-functional ethylenically unsaturated monomer and (b) 40 to about90 weight percent of at least one ethylenically unsaturated monomercopolymerizable with the hydroxy-functional monomer.

5. AMINE-FUNCTIONAL COMPOUNDS

Amine-functional compounds which are useful in combination with theanhydride-functional polymers to prepare curable compositions in thepractice of this invention should have an average of at least twoprimary or secondary amine groups per molecule. Polyamines can beprepared by methods well known in the art such as by the free radicalpolymerization of acrylic or other unsaturated monomers having primaryor secondary amine functionality, or by the reaction of amines having atleast two amine groups per molecule with a polycarboxylic acid to formpolyamide amines, or by the reaction of primary amines with epoxymaterials to produce secondary amine and hydroxyl functionality. Thepolyamines can be polymeric, typically having a number average molecularweight over 400, or lower molecular materials, such as piperazine,tetraethylenepentamine, 1,2-diaminopropane, 1,6-diaminohexane, etc. Alsouseful are the materials having a primary or secondary amine group and ahydroxyl group such as isopropanol amine, isobutanol amine, ethanolamine, etc.

The ratios of anhydride to other functional groups in the curablecompositions can be widely varied within the practice of this inventionas long as at least some of each group is present in the reactivecomposition. It is only necessary to combine the anhydride functionpolymer and other reactive materials in amounts to provide the desireddegree of crosslinking upon cure. When a combination of theanhydride-functional polymer and a polyol or polyamine is used as thecurable composition, it is preferred to provide about 0.3 to about 10hydroxyl or amine groups for each anhydride group, and especially 1 toabout 5 hydroxyl or amine groups for each anhydride group. When thecurable composition involves a combination of only theanhydride-functional polymer, an epoxide or polyepoxide, and a polyol itis preferred to provide 0.3 to about 6.0 hydroxyl groups, and about 0.3to about 6.0 epoxy groups for each anhydride group, and especially toprovide 0.5 to 2.5 hydroxyl groups and 0.5 to 2.5 epoxy groups for eachanhydride group. When the curable composition involves theanhydride-functional polymer, an acid-functional compound and apolyepoxide, it is preferred to provide 0.3 to 6.0 acid groups and 0.6to 12.0 epoxy groups for each anhydride group, and especially 2.0 toabout 5.0 acid groups and 3.0 to about 8.0 epoxide groups for eachanhydride group. If the reactive curable composition comprises theanhydride-functional polymer, an acid-functional compound, an epoxide orpolyepoxide, and a hydroxy-functional compound, it is preferred toprovide from 0.05 to about 3.0 acid groups and about 0.5 to about 4.0epoxy groups and about 0.05 to 6.0 hydroxyl groups for each anhydridegroup in the reactive system. It is especially preferred to provide 1.0to about 2.0 acid groups and 1.0 to about 3.0 epoxy groups and about 1.0to about 4.0 hydroxyl groups for each anhydride group.

The curable compositions of this invention can be cured at temperaturesranging from about room temperature up to about 350° F. When the curablecompositions are utilized as coatings, the coatings can be clearcoatings or they may contain pigments as is well known in the art.Representative opacifying pigments include white pigments such astitanium dioxide, zinc oxide, antimony oxide, etc. and organic orinorganic chromatic pigments such as iron oxide, carbon black,phthalocyanine blue, etc. The coatings may also contain extenderpigments such as calcium carbonate, clay, silica, talc, etc.

The coatings may also contain other additives such as flow agents,catalysts, diluents, solvents, ultraviolet light absorbers, etc.

It is especially preferred in the curable compositions of this inventionto include a catalyst for the reaction of anhydride groups and hydroxylgroups and/or a catalyst for the reaction of epoxy and acid groups ifpresent in the curable composition. It is especially preferred in thepractice of this invention to utilize tertiary amines and especiallyN-methylimidazole as a catalyst for the anhydride/hydroxyl reaction. Thecatalyst for the anhydride/hydroxyl reaction will typically be presentat a level of at least 0.01% by weight of the anhydride compound andpreferably 1.0 to about 5.0%.

Tertiary amines, secondary amines such as ethyl imidazole, quaternaryammonium salts, nucleophilic catalysts, such as lithium iodide,phosphonium salts, and phosphines such as triphenyl phosphine areespecially useful as catalysts for epoxy/acid reactions. The catalystfor the epoxy/acid reaction will typically be present at a level of atleast 0.01% by weight of the total acid-functional compound andepoxy-functional compound and will preferably be present at 0.1 to about3.0%.

Since the curable compositions of this invention are typically providedas multi-package systems which must be mixed together prior to use, thepigments, catalysts and other additives can be conveniently added to anyor all of the appropriate individual packages.

The curable compositions of this invention may typically be applied toany substrate such as metal, plastic, wood, glass, synthetic fibers,etc. by brushing, dipping, roll coating, flow coating, spraying, in-moldcoating or other method conventionally employed in the coating industry.

One preferred application of the curable coatings of this inventionrelates to their use as clearcoats and/or basecoats inclearcoat/basecoat formulations.

Clearcoat/basecoat systems are well known, especially in the automobileindustry where it is especially useful to apply a pigmented basecoat,which may contain metallic pigments, to a substrate followed by theapplication of a clearcoat which will not mix with or have anyappreciable solvent attack upon the previously applied basecoat.Typically, at least some of the solvent will be allowed to evaporatefrom the basecoat prior to the application of the clearcoat. In someapplications the basecoat may even be allowed to cure, at leastpartially, prior to application of the clearcoat. The basecoatcomposition may be any of the polymers known to be useful in coatingcompositions including the reactive compositions of this invention.

One useful polymer basecoat includes the acrylic addition polymers,particularly polymers or copolymers of one or more alkyl esters ofacrylic acid or methacrylic acid, optionally together with one or moreother ethylenically unsaturated monomers. These polymers may be ofeither the thermoplastic type or the thermosetting, crosslinking typewhich contain hydroxyl or amine or other reactive functionality whichcan be crosslinked. Suitable acrylic esters for either type of polymerinclude methyl methacrylate, ethyl methacrylate, propyl methacrylate,butyl methacrylate, ethyl acrylate, butyl acrylate, vinyl acetate,acrylonitrile, acrylamide, etc. Where the polymers are required to be ofthe crosslinking type, suitable functional monomers which can be used inaddition to those already mentioned include acrylic or methacrylic acid,hydroxy ethyl acrylate, 2-hydroxy propyl methacrylate, glycidylacrylate, tertiary-butyl amino ethyl methacrylate, etc. The basecoatcomposition may, in such a case, also contain a crosslinking agent suchas a carbodiimide, a polyanhydride, a polyisocyanate a polyepoxide, or anitrogen resin such as a condensate of an aldehyde such as formaldehydewith a nitrogenous compound such as urea, melamine or benzoguanamine ora lower alkyl ether of such a condensate. Other polymers useful in thebasecoat composition include vinyl copolymers such as copolymers ofvinyl esters of inorganic or organic acids, such as vinyl chloride,vinyl acetate, vinyl propionate, etc., which copolymers may optionallybe partially hydrolyzed so as to introduce vinyl alcohol units.

Other polymers useful in the manufacture of the basecoat include alkydresins or polyesters which can be prepared in a known manner by thecondensation of polyhydric alcohols and poly carboxylic acids, with orwithout the inclusion of natural drying oil fatty acids as describedelsewhere in this specification. The polyesters or alkyls may contain aproportion of free hydroxyl and/or carboxyl groups which are availablefor reaction, if desired with suitable crosslinking agents as discussedabove.

If desired, the basecoat composition may also contain waxes, rheologymodifiers, cellulose esters, or other additives to alter the appearance,drying or viscosity characteristics of the basecoat.

Typically, the basecoat will include pigments conventionally used forcoating compositions and after being applied to a substrate, which mayor may not previously have been primed, the basecoat will normally beallowed sufficient time to form a wet polymer film which will not belifted during the application of the clearcoat. The clearcoat is thenapplied to the surface of the basecoat, and the system can be allowed todry or, if desired, can be force dried by baking the coated substrate attemperatures typically ranging up to about 250° F.

Typically, the clearcoat may contain ultraviolet light absorbers orstabilizers, such as hindered phenols or hindered amines at a levelranging up to about 6% by weight of the vehicle solids as is well knownin the art. The clearcoat can be applied by any application method knownin the art, but preferably will be spray applied. If desired, multiplelayers of basecoat and/or clearcoat can be applied. Typically, both thebasecoat and the clearcoat will each be applied to give a dry filmthickness of about 0.01 to about 6.0, and especially about 0.5 to about3.0 mils.

The following examples have been selected to illustrate specificembodiments and practices of advantage to a more complete understandingof the invention. Unless otherwise stated, "parts" means parts-by-weightand "percent" is percent-by-weight and equivalent weight is on a weightsolids basis.

EXAMPLE 1

A reaction vessel fitted with a mechanical stirrer, condenser andtemperature controlling device was charged with 2210 parts Vestenamer®L-3000 (a soft, waxy polyolefin available from Huls Aktiengesellschaft,and which is derived from cyclooctene and has a number average molecularweight of approximately 1,600, an iodine number of approximately 250 andhas a steric composition comprising approximately 78% trans doublebonds, 17% cis double bonds and 5% of the double bonds have a CH₂group), 1190) parts maleic anhydride and 50 parts xylene. The reactionmixture was gradually heated from room temperature up to about 200° C.over a 21/2 hour period and maintained at approximately 200° C. forapproximately 4 hours and 40 minutes and then allowed to cool. Theanhydride-functional ene reaction product was then reduced toapproximately 50% weight solids by the addition of butyl acetate.

The anhydride-functional polymer was admixed with ULTRA FILL II® P6H49(commercially available primer/surfacer from The Sherwin-WilliamsCompany, having a hydroxyl equivalent weight of 2,333 as packaged at10.54 lbs./gal.) to provide an OH/anhydride equivalent ratio ofapproximately 1.47/1, catalyzed with 21/2% N-methyl imidazole based onthe weight solids of the anhydride-functional polymer, reduced withsuitable solvents, spray applied to metal substrates, and allowed tocure at room temperature to produce a primer surfacer having good cure,sanding characteristics and salt spray resistance.

EXAMPLE 2

A reaction vessel fitted with a mechanical stirrer, a Dean-Stark trapprimed with xylene and a temperature controlling device was charged with500 parts maleic anhydride, 750 parts Vestenamer® L-3000 and 52.1 partsxylene. The reaction mixture was gradually heated to 200° C. over a 3hour and 15 minute period and maintained at reflux at 200° C. forapproximately 3 hours, 15 minutes, at which point it was allowed to coolto 140° C. and 1,197.9 parts n-butyl acetate was then added. The mixturewas reheated to reflux at 130° C. and held at that temperature forapproximately 30 minutes after which it was allowed to cool to producean anhydride-functional vehicle at 49.9% NVM, an acid value of 225.9(229 theoretical), an iodine number of 150.3 (147 theoretical) and ananhydride equivalent weight of 245.

A curable clearcoating was prepared according to the following recipe:

    ______________________________________                                        Raw Material          Parts                                                   ______________________________________                                        Hydroxy-Functional Polymer.sup.1                                                                    204.67                                                  Solvent Blend.sup.2   145.73                                                  Byk 300.sup.3         3.00                                                    Tinuvin 292.sup.4     8.08                                                    ERL 4299.sup.5        125.26                                                  Anhydride Polymer of Example 1                                                                      310.62                                                  20% N-Methyl Imidazole/Methyl                                                                       20.20                                                   Isobutyl Ketone                                                               ______________________________________                                         .sup.1 61.2% NVM hydroxyfunctional polymer in methyl amyl ketone              comprising the free radical addition product of styrene/methyl                methacrylate/hydroxy ethyl acrylate in a weight ratio of 15/56/29.            .sup.2 Butyl acetate/methyl amyl ketone/methoxyethyl propionate/methyl        isobutyl ketone/xylene/methyl ethyl ketone in a weight ratio of               57/18/10/5/5/5.                                                               .sup.3 Flow control agent sold by BykMalinkrodt.                              .sup.4 Trademark of CibaGeigy for di[4(2,2,6,6tetramethyl                     piperdinyl)]sebacate.                                                         .sup.5 Union Carbide tradename for bis(3,4epoxycyclohexylmethyl)adipate. 

Steel panels were prepared by application of a commercial primer/sealer(E2G973 vinyl wash primer/sealer available from The Sherwin-WilliamsCompany) and by application of a commercially available blue metallicbasecoat (ULTRA-BASE® 7 F5L63/F5S112 in a 60/40 weight ratio,commercially available from The Sherwin-Williams Company). The basecoatwas allowed to flash for approximately 1 hour and then the clearcoat wasspray applied onto the basecoat surface and allowed to cure. The finalcured coating showed a 20° gloss of 74, a Konig Pendulum Hardness of 24after four weeks of air dry cure and excellent resistance to methylethyl ketone solvent.

EXAMPLE 3

A reaction vessel equipped with a Dean-Stark trap, mechanical stirrerand a temperature controlling device was charged with 450 parts maleicanhydride, 1050 parts Vestenamer® L-3000 and 62.5 parts xylene under anitrogen blanket. The trap was primed with xylene. The reaction mixturewas slowly heated to 200° C. over a period of approximately 1 hour, 50minutes, and maintained at that temperature for 41/2 hours after whichit was allowed to cool and 937.5 parts n-butyl acetate was added. Thereaction mixture was again heated to reflux (approximately 130° C.) forapproximately 30 minutes and then allowed to cool to yield ananhydride-functional polymer having an NVM of 57.6%, an acid value of159, a density of 7.98 pounds/gallon and a Gardner-Holdt viscosity of H.

A clearcoating was prepared as described in Example 2, except that theanhydride-functional polymer of Example 3 replaced theanhydride-functional polymer of Example 2 at a level to provide the samenumber of anhydride equivalents. That cured film showed a 20° gloss of84, a Konig Pendulum Hardness of 41 after four weeks and good resistanceto methyl ethyl ketone upon cure.

EXAMPLE 4

A reaction vessel equipped as in Example 3 was charged with 882 partsmaleic anhydride, 1638 parts Vestenamer® L-3000 and 105 parts xyleneunder a nitrogen blanket. The trap was primed with xylene. The reactionmixture was heated to 185° C. over approximately a 1 hour period atwhich point refluxing and azeotroping of water began. The heating wascontinued to 200° C. and held at that temperature for 31/2 hours atwhich point 975 parts of xylene was added and the mixture was refluxedat about 150° C. for one hour to azeotrope any remaining water.

While this invention has been described by a specific number ofembodiments, other variations and modifications may be made withoutdeparting from the spirit and scope of the invention as set forth in theappended claims.

The entire disclosure of all applications, patents and publicationscited herein are hereby incorporated by reference.

The invention claimed is:
 1. An anhydride-functional polymer obtained byreacting under ene reaction conditions a mixture of reactantscomprising:(i) 20 to 70 percent by weight of an unsaturated anhydridehaving the structure: ##STR7## wherein R₁ and R₂ are each independentlyhydrogen, alkyl of 1 to about 6 carbons, or alkoxy of 1 to about 6carbons, or a halogen; and (ii) 30 to 80 percent by weight of at leastone polyolefin having at least two carbon-carbon double bonds in thepolyolefin backbone and having an average of at least three carbon atomsin the polyolefin backbone between the carbon-carbon double bonds. 2.The anhydride-functional polymer of claim 1 wherein the backbone of thepolyolefin is comprised primarily of repeating units having thestructure:

    --[--(CR.sub.3 R.sub.4).sub.x --CHR.sub.5 --CH═CH--]--

wherein each x is individually a number from 2 to about 15; and R₃, R₄and R₅ are each individually hydrogen, or a linear, branched or cyclicaliphatic group of 1 to about 18 carbon atoms.
 3. Theanhydride-functional polymer of claim 1 wherein the polyolefin comprisesthe structure:

    Z--CH═CH--[--(CR.sub.3 R.sub.4).sub.x --CHR.sub.5 --CH═CH--].sub.n --Z

wherein each x is individually a number from 2 to about 15; R₃, R₄ andR₅ are each individually hydrogen, or a linear, branched or cyclicaliphatic group of 1 to about 18 carbon atoms; each Z is individuallyhydrogen or a linear, branched or cyclic aliphatic group of 1 to about36 carbons; and n is a number between 2 and 5,000.
 4. Theanhydride-functional polymer of claim 3 wherein n is between 2 and 100.5. The anhydride-functional polymer of claim 3 wherein n is between 8and
 28. 6. The anhydride-functional polymer of claim 1 wherein thepolyolefin is obtained by the metathesis of a cyclic olefin.
 7. Theanhydride-functional polymer of claim 6 wherein the cyclic olefin iscyclooctene.
 8. The anhydride-functional polymer of claim 2 wherein x isbetween 4 and
 12. 9. The anhydride-functional polymer of claim 2 whereinR₃, R₄ and R₅ are each hydrogen.
 10. A process for preparing ananhydride-functional polymer which process comprises admixing under enereaction conditions:(i) 20 to 70 percent by weight of an unsaturatedanhydride having the structure: ##STR8## wherein R₁ and R₂ are eachindependently hydrogen, alkyl of 1 to about 6 carbons, or alkoxy of 1 toabout 6 carbons, or a halogen; and (ii) 30 to 80 percent by weight of atleast one polyolefin having at least two carbon-carbon double bonds inthe polyolefin backbone and having an average of at least three carbonatoms in the polyolefin backbone between the carbon-carbon double bonds.11. The process of claim 10 including the additional step of removingwater from the reaction mixture and/or polymer product by codistillationwith an azeotrope-forming solvent.
 12. The process of claim 10 includingthe additional step of filtering a solvent solution of the polymerproduct to remove insoluble impurities.